This is a good example of the kind of things that can happen over time to wiring harnesses, especially around where they bend over and over:



Like maybe around where the engine harness goes to the fire wall. You might not realize it but engines move quite a bit while driving. I once drove my truck without a hood and was amazed just how much it moves around.

Also are you sure you got the correct part #s, sounds strange this happened to one bank after changing the knock sensors and wiring.

 

This, in bold, is correct

 

Yes drift king was correct all along. My bad. My reading and my testing are all running together. Mt goat thanks fot the links I will check that and see if it gets me any further. Also you asked if I got the right parts, Well the knock sensors I took out had "ND" on the side so I replaced them with the denso sensors and a factory Toyota harness. So..I think so. Im not sure how to test the sensors without pulling it all apart again? Thanks again guys. The amount of knowledge here blows my mind.....

 

I'm a believer now

 

Ok. I followed the trouble shooting steps provided by mt goat. I unplugged the harness leading to the knock sensors, hooked up scan tool And got a reading between 8.1-9 kHz. Spec is 7.1-7.6. Tech info says to replace if over spec. But what are the Odds of me getting 2 bad knock sensors at the same time. Well I decided to ohm the old knock sensors that I already removed and there was no continuity in either sensor. So.....my sensors were never bad. Maybe the harness I replaced? But why do they both read out of spec now? Is there something else that can set the knock sensor code off. If my engine was knocking "which I can't hear" it would set the code for knock sensor off right? They would do their job and adjust timing to compensate I think. I'm stumped.

 

Yes, I'll say it again...the wiring going from the knock sensor/knock sensor harness to the ECU. Step #2 here: http://www.ncttora.com/fsm/1996/SIL/...e/cip0325p.pdf That was when I was assuming the new sensors and harness you installed are good but the wiring between that and the ECU might have a break. If your testing was accurate and the sensors are out of spec I'd suspect you were given the wrong parts.

 

Mt goat. I remember what u said about the harness to the ECM and u plan to check that. I guess what I was asking is... I know a bad wire or bad sensor will throw the code but what about actual knocking? Will properly functioning knock sensors adjust for this or will the knock it's self throw the code. I'm just trying to make sure I'm chasing the right trouble and not something deeper in the engine. And I Didnt know if my readings 8.1-9 were really far off or if they would change with rpm? I dint procede to check reading back to the ECM because I didn't know what pins to use. I couldn't find it in the tech info link u sent. Thanks again.

 

I don't know, I'd guess if something that causes knocking (like carbon build-up) would set off that code the FSM would list it as a possible problem area. But I like your thinking, outside the box.

Yeah, the electrical wiring diagrams (EWDs) are a little harder to find and they are very year/model specific. Try searching the 3.4 swap section, I think its got some good info on finding EWDs for your vehicle. https://www.yotatech.com/forums/f160/

 

Ok here's where I'm at now. 2 new knock sensors, new ks harness. Checked readings at ks harness, spec says 7.1-7.6 my readings were about 8 but readings change with rpm. I'm reving the engine to get these reading. Hopefully that the correct way to test. Then instead of checking continuity from the ECM to the ks harness I checked the readings again but this time checked at the ECM while having someone rev engine up to 4k. Readings were 7-8 and changed with rpm. I'm really out of ideas. Any suggestions? I'm I performing my
tests right?

 

Does anyone think this could be a ba ECM? What are some of
the signs? Wouldn't I be having
more problems if the ECM was going bad?

 

Is there any signs of this truck being in a flood? That would be a possible way the ECU could be damaged. Sorry I'm not sure on signs, I've never seen a ECU go bad. My guess is a bad ECU would be like any computer going bad, it just depends on what goes wrong with it.

 

No signs of flood damage at all. I took out the 2 new knock sensors I installed and the new wiring harness and got 2 more knock sensors and another harness. Put it all back together and still the same problem. Im totally stumped.

 

If you want to eliminate the ECU possibility I'd look for a bone yard ECU (must be the same year/model) and swap it in. If its the same problem with a different ECU you could probably resell it to someone else.

I still suspect the wiring harness between the ECU and the KS harness connector. Maybe an intermittent short, how quickly does the CEL come back after clearing?

 

The CEL comes back on as soon is the Rpm goes above 3k

 

So you can clear the code, restart the engine and rev it above 3000 and the CEL is back on in seconds?

 

Yes that is exactly right

 

That's not very intermittent then, yes it. That's actually a good thing though because its easier to find the source of a constant problem.

 

Yea but I still can't find it. Maybe I'm testing wrong. How exactly should I test the wiring u suspect. From the harness to the ECM?

 

Going back to the FSM link in my post #26. Looking at step #2 it sends you to this link: http://www.ncttora.com/fsm/1996/SIL/...csy/htutdc.pdf

 

Well I will check everything again and see what I come up with. I'm sure I have good KS now. I tested these before I insalled them and the harness. I'm still wondering if this could be a timing or actual "knocking" issue due to pre detonation or something.